McCulloch Chain Saws

[mogulmasher]

I also have a cp70 in a box to compare. I've never really heard how the cp/sp70 hangs with the pm700 or 7-10.

 

[Jethro 2t sniffer]

I beg to differ. I am very inconsistent. And out the box is almost always the sharpest they will ever be. Ron

Well practice makes perfect lol

 

[mogulmasher]

Forgot cp70 wasn't torn down all the way. You can just make out 3 open finger ports though. This seems to differ from the 7-10 and pm700 a bit. Anyone comment on how they run?

 

[mogulmasher]

And also sp80 cylinder. Looks very similar to 7-10 design.

 

[Jethro 2t sniffer]

And also sp80 cylinder. Looks very similar to 7-10 design.
View attachment 792666 View attachment 792667 View attachment 792668

A guy on you tube with some nice ones says the CP70 went better than both 7-10 and 700. Thanks for the pictures. Quite interesting

 

[Jethro 2t sniffer]

This guy..



Certainly runs a saw or two

 

[Jethro 2t sniffer]

Actually he was talking sp not cp weather there is a difference or not don't know

 

[vinnywv]

Forgot cp70 wasn't torn down all the way. You can just make out 3 open finger ports though. This seems to differ from the 7-10 and pm700 a bit. Anyone comment on how they run?
View attachment 792665

The "3 finger" is whats in a 10-10. Thats interesting. A pro 10-10 automatic to be precise.

 

[Goinwheelin]

Bored at work so I grabbed some Delrin and made new starter shaft bushings for a couple of my Macs. I used the 7-10 as my test bed so hopefully there isn’t too much of a dimension swing and they will fit the other saws.

 

[Jethro 2t sniffer]

Bored at work so I grabbed some Delrin and made new starter shaft bushings for a couple of my Macs. I used the 7-10 as my test bed so hopefully there isn’t too much of a dimension swing and they will fit the other saws.
View attachment 792791 View attachment 792792

Good job yeah some don't have the nylon and a brass bush if I remember rightly

 

[Goinwheelin]

Yeah I thought about reaming out the starter housing and making a bronze bushing to press in there but that might be overkill lol.

 

[Maintenance supervisor]

Yeah I thought about reaming out the starter housing and making a bronze bushing to press in there but that might be overkill lol.

Does it have the tiny notch?

 

[Goinwheelin]

Yes it does.

edit: it had the plastic bushings in it but they were pretty much toast.

 

[2broke2ride]

The "3 finger" is whats in a 10-10. Thats interesting. A pro 10-10 automatic to be precise.

I thought my early 7-10 had the three finger ports but it's been forever since I looked at it. I'm glad we are documenting all of this, it will be good info for when I get back into mine. I still think I have a piston to cylinder mismatch or something that is effecting the port timing.
I also thought about possible "free porting" from the piston skirt maybe being too short. I will see when I get back to it.
I have to get through some customer work first.

 

[Jethro 2t sniffer]

I thought my early 7-10 had the three finger ports but it's been forever since I looked at it. I'm glad we are documenting all of this, it will be good info for when I get back into mine. I still think I have a piston to cylinder mismatch or something that is effecting the port timing.
I also thought about possible "free porting" from the piston skirt maybe being too short. I will see when I get back to it.
I have to get through some customer work first.

Really hope ya get going

 

[rwoods]

From the land down under comes a new (and more likely) 82cc hp figure - well at least for the PM8200. 5.6 horsepower. Zoom in on this brochure.

https://www.ebay.com/itm/Vintage-Mc...185803?hash=item3b1a5a250b:g:Qg8AAOSwU1hbiyqt

Ron

 

[mogulmasher]

From the land down under comes a new (and more likely) 82cc hp figure - well at least for the PM8200. 5.6 horsepower. Zoom in on this brochure.

https://www.ebay.com/itm/Vintage-Mc...185803?hash=item3b1a5a250b:g:Qg8AAOSwU1hbiyqt

Ron

Good info right there. I thought they'd be closer to 6hp though. Oh well.

HP numbers would be another thing to document here too. With verified sources, like brochures or actual Dyno runs. I was searching info on older 80/87cc Macs earlier and wound up on a vintage karting thread that quoted some old hp numbers from brochures. Highest I saw for one of the old 80cc motors was 5hp, but some models like D30 was 3.9hp.

 

[sawfun]

That horsepower figure does not tell the whole story as far as torque goes and how and when that applies.

 

[mogulmasher]

That horsepower figure does not tell the whole story as far as torque goes and how and when that applies.

Yes I agree 100%. Most old Macs have a lot more torque than their modern counterparts. HP certainly doesn't mean everything, it takes torque to get work done. If we could spin them a couple thousand more rpm the HP would be right up there too.

 

[PogoInTheWoods]

I'm glad we are documenting all of this, it will be good info for when I get back into mine.

Precisely why we're trying to keep the topic alive. Someone will get to the bottom of it sooner or later.